In Bat Deaths, a Catastrophe in the Making?

A “biodiversity crisis”: that’s how some conservationists describe new numbers released this week by the federal Fish and Wildlife Service on so-called white-nose syndrome. According to the agency, 5.7 million to 6.7 million bats have died from the fungal ailment in eastern North America since an epidemic first broke out in upstate New York in 2006.

The new numbers are striking, and far higher than the previous bat mortality estimate of one million released in 2009, yet it is hard to put the number into perspective because researchers lack baseline data for many bat species populations from before the disease started demolishing colonies.

What is known is that when the fungus gets into a cave or mine where bats are hibernating, 70 to 90 percent of the bats die. In some cases, the mortality rate is 100 percent.